1. Field of the Invention
The present invention relates to a cooling system adapted to an ice making machine, a refrigerator, a freezer, an air conditioner and the like, more particularly to a cooling system which is operated alternately at a cooling mode and a defrost mode.
2. Discussion of the Prior Art
A conventional cooling system of this kind comprises a compressor for supplying refrigerant under pressure, a condenser for cooling and condensing the refrigerant supplied from the compressor, a liquid receiver arranged to temporarily store the condensed refrigerant supplied from the condenser, an expansion valve for expanding the refrigerant supplied from the liquid receiver, and an evaporator arranged to effect evaporation of the expanded refrigerant for cooling the surrounding thereof. In the cooling system, a supply conduit of the refrigerant from the compressor to the condenser and a supply conduit of the refrigerant from the expansion valve to the evaporator are connected at their intermediate portions by means of a separate conduit to directly supply the refrigerant from the compressor to the evaporator during operation at a defrost mode thereby to heat the evaporator.
In the case that the compressor was installed at a place near the evaporator in the cooling system, noises in operation of the compressor and decrease of the cooling efficiency of the evaporator caused by exhaust heat of the compressor were problems for solution. If the compressor was installed at a place apart from the evaporator to solve the problems in the cooling system, the defrost conduit for direct supply of the refrigerant from the compressor to the evaporator would be elongated, resulting in an increase of cost of the component parts and cost for installation of the cooling system. Particularly, in the case that the evaporator is installed indoor while the compressor is installed outdoor, it is required to provide a separate conduit for connection of the indoor unit and the outdoor unit. If the conduit for defrost was elongated, a large amount of refrigerant would be required for the entirety of piping in the cooling system. If the refrigerant was insufficient in amount, the efficiency of cooling and defrosting in operation would be decreased.